Problem 3 - A single LED flashes above a selected keypad
product button.
Solution 1 - Ensure the grind is not too fine and/or the tamp too hard.
If the grind is too fine and/or the tamp too hard, water-flow may be restricted. This slows down or
stops the movement of the flowmeter’s impellor causing the control board to not register a proper
pulse signal. A flashing LED above the selected keypad button signals the operator that something
is wrong.
1. Ensure the LED consis-
tently goes into flashing
mode when you press it.
2. When coffee is packed too
tightly, water flow is restriced.
Tamp with less pressure.
3. You can also try adjusting
the grind coarser.
Solution 2 - Check for and repair a faulty ground connection.
The control board on the AV, or automatic models, as well as the auto-fill board on the EE or semi-
automatic models, each have step-down transformers that drop 220vac down to 24vac. The voltage
that has been dropped down is then passed through a rectifier which converts the AC voltage into
DC voltage. AC voltage alternates it’s direction of flow, whereas DC voltage flows in one specific di
-
rection, either towards positive (+), or towards negative (-). Without a proper ground connection, the
DC voltage has no reference point for 0 or neutral. This causes sporatic behavior in DC componets
such as the flowmeters which can cause erratic shot volume.
See Problem 1, Solution 4 for detailed instructions.
